1. Field of the Invention
The present invention involves a method for absorbing oil spills utilizing a material, the absorbing properties of which for cleaning up contaminating oil spills, have previously gone unrecognized. More specifically, the invention involves utilizing coconut coir pith as an absorbent medium in cleaning up spilled oil.
2. Description of the Prior Art
In recent years there has been an ever increasing awareness of the devastating environmental damage that can be caused by oil spills. It is well recognized that an extremely important aspect of minimizing damage from an oil spill is the prompt containment and collection of the spilled oil. Effective collection of spilled oil ideally involves the absorption of oil in some absorption medium that can be easily raked or otherwise picked up from the surface upon which the oil has spilled. Nevertheless, despite intensive research and testing, the only absorption substances which are at all suitable for use in cleaning up oil spills involve significant defects or difficulties.
Some conventional oil absorbents currently in commercial use are made from polypropylene. Polypropylene absorbs hydrocarbons but is hydrophobic. That is, it is water repellent. However, polypropylene has a limited oil absorbing capacity, and is not at all biodegradable. Also, polypropylene is quite expensive to use in the large quantities necessary to deal with major oil spills.
Efforts have been made to find other oil absorbent materials suitable for cleaning up oil spills which are biodegradable. For example, peat moss has been used for this purpose. However, in the form in which it is obtainable commercially, peat moss contains a significant amount of impurities such as a sand and carbon. Also, peat moss does not float on water well and is limited in its absorption capacity for oil. For example, one pound of peat moss will absorb about five pounds of oil. In addition, peat moss is not totally biodegradable.
Another substance which has been tested for its oil absorbent capacity in cleaning up oil spills is a seaweed-based product that is normally sold as a soil conditioner. This product is sold under the registered trademark, Afrikelp, and is comprised of a blend of selected brown seaweeds found off the southern coast of the African continent. However, this product is rather expensive and has a limited oil absorption capability.
According to the present invention, a substance has been found which is readily available and which makes an ideal oil absorption medium. Moreover, this product is completely biodegradable. Specifically, the present invention involves the use of coconut coir pith as an oil absorption medium in cleaning up oil spills.
Coconut coir pith is a residual byproduct produced from making coconut fiber ropes and mattresses. Coconut coir pith is a portion of the coconut husk that falls as a residual powder when coconut husk fibers are crushed in the manufacture of ropes and other products. Coconut coir pith is currently sold commercially for use in landscaping for its moisture barrier properties. It is typically sold for use in golf courses. A layer of coconut coir pith is spread upon a dirt surface to be sodded. The sod is then laid upon the coconut coir pith layer. The coconut coir pith aids in the retention of moisture by the sod and thereby aids in the prevention of burning of the sod by the sun in hot weather. Coconut coir pith is also conventionally used under plants and floor pots for the purpose of retaining moisture above to enhance plant growth. While coconut coir pith may be obtained from many different sources, one source of supply is Marvel Collections Ltd., located at 71 Ward Place, Colombo, Sri Lanka.
Although coconut coir pith has been commercially available for many many, years, it""s oil absorption properties and potential use for absorbing oil in oil spill situations has heretofore gone unrecognized. I have discovered that coconut coir pith, particularly when utilized in small particulate sizes, serves as an ideal oil absorption medium. Moreover, coconut coir pith may be utilized to clean up oil spills not only on solid surfaces, such as highways, concrete slabs and soil, but also upon the surfaces of bodies of water. Coconut coir pith floats and absorbs oil in preference to water. One pound of coconut coir pith will absorb between about eight and ten pounds of crude oil.
A very significant advantage of coconut coir pith over conventional oil absorption substances used to absorb oil in oil spill situations is that coconut coir pith is one hundred percent biodegradable. Coconut coir pith floats upon water and remains afloat even when saturated with oil. Coconut coir pith absorbs oil, coolants, solvents and other oily materials that float on water.
Coconut coir pith is entirely nontoxic. It is light in weight and creates very little dust even when thrown a considerable distance onto a surface from which oil is to be absorbed.
Furthermore, coconut coir pith has an additional advantage in that it retains its consistency, even when spread on water and saturated with oil. That is, it will not turn to xe2x80x9cmushxe2x80x9d even when wet and saturated with oil. This feature allows the oil-saturated coconut coir pith to be scooped or raked from the surface of a body of water without great difficulty.
When utilized to absorb oil on the surface of a body of water, coconut coir pith absorbs more than one gallon of oil per pound. The extent of absorption depends upon the viscosity of the oil. Moreover, coconut coir pith reduces volatile vapors from the oil by up to 90 percent. Coconut coir pith is ideal for use in cleaning up ocean oil spills, as well as for use in cleaning up both outdoor and indoor spills on the ground or on pavement.
In one broad aspect of the invention may be considered to be a method of collecting oil upon a surface comprising: dispensing a quantity of coconut coir pith across the surface, whereupon the oil is absorbed into the coconut coir pith, and thereafter removing the coconut coir pith from the surface. Preferably the coconut coir pith is dispensed in particulate form in which the particles have an average maximum dimension of no greater than one and one-half inches. The coconut coir pith can also be used in other forms such as bullets, grains, gravels, pellets, briquettes, and other shapes and sizes
Coconut coir pith is sold commercially in granular, loose, and disk-shaped forms. At present, coconut coir pith is often sold in disk-shaped cakes having a diameter of about three inches and a thickness of about one inch. If the substance is obtained in disk form, it is advisable to break the disks up into smaller particles. The disk-shaped cakes in which coconut coir pith is sold commercially may be passed through a series of pairs of counterrotating, crushing rollers to reduce the size of the cakes at a ten to one ratio. The pairs of rollers are spaced at decreasing distances. The final pair of rollers is equipped with blades that chop the coconut coir pith into particles of between about one-quarter inch and one inch in size. The particles of coconut coir pith are dispersed from the final pair of rollers into a hopper and channeled into a bagging machine.
According to one embodiment of the present invention the coconut coir pith is in the form of particles having an average maximum dimension of no greater than about one and one-half inches.
One primary area of application of the method of the invention is in cleaning up petroleum-based oil spills in bodies of water such as oceans, lakes, and rivers. To aid in the cleanup, it is often advisable to surround the area of the surface upon which the oil is present with a spill containment boom. Preferably the spill containment boom has a floating portion that includes coconut coir pith confined within a surrounding, elongated, porous covering. The coconut coir pith within the covering maintains the boom afloat, and the oil that makes contact with the boom is absorbed within the coconut coir pith located within the porous covering, as well as by the quantities of coconut coir pith thrown onto the oily surface of the water surrounded by the containment boom.
A further advantageous feature of the invention is that a very substantial portion of the oil can be extracted from the coconut coir pith once the oil-saturated coconut coir pith has been removed from the site of the oil spill. To extract the oil, the saturated coconut coir pith is pressed or squeezed by rollers or by a press. As the oil is squeezed out of the coconut coir pith, it is filtered and collected in a receptacle. It is possible to recover between about seventy-five percent and about ninety percent of the oil absorbed by the coconut coir pith in this manner.
Furthermore, the recovered oil, which would otherwise constitute hazardous, contaminated waste, is in a reusable form. In addition, once the absorbed oil has been squeezed out, the coconut coir pith also is available for reuse to collect oil from future spills. The coconut coir pith can be reused about three or four times, provided that the oil is pressed out of it following each use. After that, the coconut coir pith can either be incinerated or used for landfill. Coconut coir pith is one hundred percent biodegradable so it will totally decompose when used as landfill.
In another broad aspect, the invention may be considered to be a method of collecting spilled oil from a surface comprising: spreading a quantity of coconut coil pith upon the surface, whereupon the coconut coir pith absorbs the oil, and recovering the coconut coir pith with the oil absorbed therein.
While the invention is equally applicable to oil spills on land as well as at sea, use of the invention to control oil spills in water represents a very major application of the invention. In this aspect, the invention may be considered to be a method of cleaning up a petroleum spill in water comprising: dispensing upon the surface of water on which a spill has occurred a quantity of coconut coir pith, which thereupon absorbs petroleum while remaining afloat, collecting the coconut coir pith with petroleum absorbed therewithin, and removing the coconut coir pith from the water. These steps are preferably followed by squeezing the coconut coir pith following the step of removal, and recovering petroleum for use from the coconut coir pith as it is squeezed out.
The method of the invention is preferably practiced for cleanup of petroleum spills in water by confining the petroleum spill. This may be accomplished by placing socks about the area of the spill. The socks are formed of porous sheaths filled with additional quantities of the coconut coir pith.
The invention may be described with greater clarity and particularity by reference to the following examples and accompanying drawings.